给 Ubuntu 选一个最快的更新源，这事儿其实很简单，但不少新手朋友一上来就被各种源列表搞晕了。别急，咱们分两条路走——一条是图形界面点点鼠标，另一条是直接改配置文件，后者更适合批量操作或者服务器环境。往下看，一步到位。
图形界面：傻瓜式操作
如果你的 Ubuntu 有桌面环境，最直观的方法就是打开 设置 → 软件和更新，界面长这样：
进来之后，找到“下载自”那一栏，下拉菜单里选择 其他站点：
接下来有两种选择：一是直接点 选择最佳服务器，系统会自动测试并挑出最快的镜像；二是手动从列表里选一个你信得过的源。选好之后系统会提示输入密码，确认就完事了：
关闭窗口后，系统会自动运行 sudo apt-get update 刷新缓存，更新完成就能用上新源了：
命令行：手动替换阿里源（以 Ubuntu 18.04 为例）
安装完 Ubuntu 18.04 后发现默认的国外源慢得像乌龟？那就直接换成国内源吧。最常用的就是阿里源，速度稳定，配置也不复杂。
第一步：备份原始源文件
养成好习惯，先备份再动手：
cp /etc/apt/sources.list /etc/apt/sources.list.bak第二步：编辑 sources.list
用你喜欢的编辑器（比如 vim、nano）打开 /etc/apt/sources.list，把里面的内容全部替换成以下阿里源条目：
# 阿里源
deb https://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb https://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb https://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
第三步：更新并升级
保存文件后，运行以下命令让新源生效：
sudo apt-get update
sudo apt-get upgrade
如果一切正常，你会看到下载速度明显提升。
其他国内源备选
除了阿里源，下面这几个也是国内常用的高速镜像，适合不同网络环境。复制粘贴时记得把版本代号改成你自己的（比如 bionic 对应 18.04，focal 对应 20.04，jammy 对应 22.04）。
中科大源
# 中科大源
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
163 源
# 163源
deb https://mirrors.163.com/ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.163.com/ubuntu/ bionic-security main restricted universe multiverse
deb https://mirrors.163.com/ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.163.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb https://mirrors.163.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.163.com/ubuntu/ bionic main restricted universe multiverse
deb-src https://mirrors.163.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src https://mirrors.163.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.163.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src https://mirrors.163.com/ubuntu/ bionic-backports main restricted universe multiverse
清华源
# 清华源
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
注意：上面所有示例中的 bionic 是 Ubuntu 18.04 的版本代号，如果你用的是 20.04 就换成 focal，22.04 换成 jammy，24.04 换成 noble，以此类推。不确定的话，在终端输入 lsb_release -c 就能看到自己的版本代号。
换好源，apt 的速度立马起飞。以后装软件、更新系统再也不用干等了。
